In general, portable terminals such as mobile phones are provided with liquid crystal display devices which show various kinds of information on display surfaces thereof. Large-sized display surfaces can show a great deal of information (such as document text) at one time and television pictures in large size. On the other hand, such large-sized display surfaces make the entire devices increased in size and prone to be too bulky to carry.
In light of such circumstances, for example, a mobile phone may be configured to include two display surfaces which can be switched between a state of being vertically overlapped and a state of being aligned sideways (for example, Patent Document 1). According to this mobile phone, when the two display surfaces overlap, the device becomes smaller in size and less prone to be too bulky to carry. Meanwhile, when the two display surfaces are aligned sideways, the mobile phone can display image in a large screen.